I picked up a betta about 3 weeks ago from petco. I placed him in a non cycled 5 gallon aquarium, heated to 79 degrees. He ate the first 3-4 days, but has since went on a hunger strike for last 2.5 weeks. He also has cut back on his swimming and spends a lot of time sitting on the bottom. Honestly I wasn't worries too much about this but it has gone on for a long time now. I have tried betta pellets and frozen blood worms without success.

Originally, this struck me as maybe ammonia poisoning, but I have been vigilantly watching ammonia levels and doing regular water changes (using dechlorinated water). About a week ago, thinking maybe something toxic got into the tank during setup I moved him to approximately 1.5 gallon bowl that is getting daily 100% water changes and added aquarium salt. He still hasn't eaten anything, but yesterday produced a nice large bubblenest . I have pulled out a flashlight and magnifying glass and see no visible sign of infection.

Is there anything else I can do for him? Is there any broad based medications that might be worth a shot? Just how long can he last without food?

I picked up a betta about 3 weeks ago from petco. I placed him in a non cycled 5 gallon aquarium, heated to 79 degrees. He ate the first 3-4 days, but has since went on a hunger strike for last 2.5 weeks. He also has cut back on his swimming and spends a lot of time sitting on the bottom. Honestly I wasn't worries too much about this but it has gone on for a long time now. I have tried betta pellets and frozen blood worms without success.

Originally, this struck me as maybe ammonia poisoning, but I have been vigilantly watching ammonia levels and doing regular water changes (using dechlorinated water). About a week ago, thinking maybe something toxic got into the tank during setup I moved him to approximately 1.5 gallon bowl that is getting daily 100% water changes and added aquarium salt. He still hasn't eaten anything, but yesterday produced a nice large bubblenest . I have pulled out a flashlight and magnifying glass and see no visible sign of infection.

Is there anything else I can do for him? Is there any broad based medications that might be worth a shot? Just how long can he last without food?

No other fish. The filter current may of been stressing him and an issue in the 5 gallon I had him in, but he has been in an unfiltered 1.5 gallon bowl for the last week (yes I am doing daily water changes on it) and he still has not eaten.

No other fish. The filter current may of been stressing him and an issue in the 5 gallon I had him in, but he has been in an unfiltered 1.5 gallon bowl for the last week (yes I am doing daily water changes on it) and he still has not eaten.

After a betta is moved it sometimes takes them a week to settle into their new tank and surroundings.

After a betta is moved it sometimes takes them a week to settle into their new tank and surroundings.

Sometimes longer.

Is he still pooping?

I guess what made me move him from the 5 gallon is he was eating and looked pretty well adjusted, but then stopped. Since I could not see any disease evident, I though it might be something in the water.

It is possible he is still adjusting to the smaller aquarium and why he has not started eating again. Absent any other suggestion I am just going to keep offering him food in the smaller tank and hope he eventually starts eating.

He is no longer pooping and hasn't for awhile, I just don't think there is anything left in his system. He is definitely not bloated or constipated.

Intestinal parasites can cause loss of appetite, I think you should treat him with an anti-parasitic tablet that contains the ingredients metronidazole and praziquantel. It is well past the point of a normal adjustment period, in my experience. If it was a bacterial infection, the fish would be worse, probably very dead by now. Parasites are very treatable and the medication isn't particularly harsh. When I've treated fish for parasites in the past, they reacted very well to treatment and started eating again after about 5 days. It's worth a shot. I have had some success with Jungle's Parasite Clear tablets.

Good news, he ate today. I ended up treating with an antiparasitic, and continuing with lots of water changes. I am crossing my fingers that he continues to improve. I am going to let him get some strength back and put him back into the 5 gallon.